Hydrogen is commonly heralded as a local weather hero as a result of when it’s used as a gas in issues like buses or metal manufacturing, there aren’t any direct carbon emissions (or associated warming) to fret about. As the world tries to chop down on our use of fossil fuels, there may very well be loads of new demand for this carbon-free power supply.
But how hydrogen is made might decide simply how useful it’s for the local weather. That’s the place the rainbow is available in. (I’ve added an at-a-glance desk beneath so you possibly can untangle all these colours.)
Last week, the European Commission launched guidelines that outline what “renewable” hydrogen is: in different phrases, what it means for hydrogen to be inexperienced. There was additionally a captivating story in Science final week about naturally occurring, or gold, hydrogen.
So let’s dive into the hydrogen rainbow and discover the place this gas of the longer term may come from.
What do we’d like hydrogen for?
We already use loads of hydrogen in the present day: international demand was 94 million metric tons (Mt) in 2021. Most of that was used for oil refining, in addition to manufacturing of ammonia (for fertilizer) and methanol (for chemical manufacturing).
That is more likely to change sooner or later, as a result of it’s additionally an excellent substitute for fossil fuels in transportation, heavy trade, and different sectors. If international locations maintain their local weather pledges, hydrogen demand might attain 130 Mt by 2030, and a few quarter of that might be for brand spanking new makes use of.
The drawback is, making hydrogen in the present day overwhelmingly requires fossil fuels, normally pure gasoline. In so-called “gray” hydrogen manufacturing, pure gasoline reacts with water, producing hydrogen gasoline and giving off carbon emissions.
It doesn’t should be that method, although. For one factor, we might attempt to seize the carbon emissions from fossil-powered hydrogen manufacturing (this technique yields so-called blue hydrogen). This is a reasonably controversial method, as a result of carbon seize is dear and doesn’t at all times work effectively.